DE3638287A1 - SOLID-BODY IMAGE RECORDING DEVICE WITH EVEN DOPE DISTRIBUTION AND METHOD FOR THE PRODUCTION THEREOF - Google Patents

Description

The invention relates to a method of manufacture a solid-state image recording device according to the Preamble of claim 1, to a method for Production of a silicon substrate according to the preamble of claim 11 and a solid-state imaging device according to the preamble of claim 22.

In general, the invention relates to a charge coupled device or CCD solid-state image recording device or V-OFD type image converter device (vertical overflow Drain type), in which excess electrical charges to the substrate and thus removed. About that the invention also relates to a method of manufacture such a solid-state image recording or image converter device of the V-OFD-CCD type.

Solid state imaging devices of the CCD type used to an ever greater extent and continuously developed. Generally includes a solid state imaging device of the CCD type a plurality of photosensor elements, along rows and columns or are arranged in a matrix on a semiconductor substrate. Each solid-state image pickup device also includes one A plurality of vertical shift registers and one A plurality of horizontal shift registers. The vertical Shift registers have a CCD structure and are located on one side of each column of the  Photosensor elements, with the vertical shift registers Have transmission sections, each of which is assigned to an adjacent photosensor element in order the electrical ones obtained from the photosensor elements Transfer charges to the horizontal shift registers to be able to. The charges in a horizontal shift register are used as image data via an output circuit output, each over a single horizontal Line, with the charges or image data of the received Correspond to light intensity.

This type of solid-state imaging device minority charge carriers in each photosensor element or minority carriers, in accordance with the intensity of that striking the photosensor elements Light. These minority carriers become assigned Transfer section of the shift register, each next to a vertical column of photosensor elements is arranged. In every shift register the minority carriers become the neighboring ones in turn Transmission sections of this shift register and transferred towards the horizontal shift register, so that through the output port of the already mentioned Output circuit of the horizontal shift register for each horizontal line of image signals for individual image areas in accordance with the Intensity of that received by each photosensor element Light can be output.

Becomes a photosensor element of too strong a light intensity exposed, too many charge carriers are generated. These charge carriers are transferred to the shift register, without the photosensor element having any influence on this or could hold back or limit these charges. This creates a so-called brightening or overexposure effect in the captured or converted image  obtained, which is also known as the blooming effect. To avoid this blooming effect, a so-called Overflow drain area in the neighborhood of one each photosensor element can be provided. In this Fall, however, it is impossible to use the picture elements or pixels to miniaturize and an image converter device with to obtain high picture element density. Too much of it of the available area would be Drain areas are taken. To the previously mentioned To overcome problems, so-called V-OFD Solid state imaging devices used. With these V-OFD solid-state imaging devices excess charge carriers in or through the substrate derived without special overflow drain areas are required in the circuit level.

In the proposed V-OFD solid-state imaging device becomes a potential barrier with regard to charge carriers with a predetermined height in a predetermined Depth below the major surface of the substrate due to the presence of a trough layer or potential trough layer (well-layer). Licking through of charge carriers into the substrate along the vertical axis can thus be limited or controlled. Strikes light with high intensity on the photosensor elements on so that a large number of charge carriers is generated, the excess charge carriers flow down to the level of the barrier and then over the substrate. This prevents the excess Loads get into the vertical shift register.

If the solid-state image pickup device of the V-OFD type consists of an n-type silicon single crystal substrate which has been formed from an n-type silicon single crystal body produced by means of the Czochralski method (CZ method), the image pickup device is usually used creates a fixed, streak-like noise pattern. This is shown in FIG. 5. In addition, white dots appear due to errors due to crystal dislocations, crystal vacancies, etc.

The fixed, streak-like noise pattern is due to a non-uniform distribution of the doping material of the n-type, which can be, for example, phosphorus, evoked. This doping material is required thus pulled an n-type silicon single crystal body can be. The concentration non-uniformity can be up to 5%, for example. Consequently can distances between different concentrations range between 60 and 400 µm. The caused by the non-uniform concentration Streaking is called "striation" (streaking) and has its cause in the environmental or State fluctuations in the area of the solid-liquid interface when pulling the crystal. The main factors will be seen in that the proportions of boron (B) and Oxygen (O) change from the inner peripheral area the quartz crucible are pulled out or emerge, and indeed in the area of the liquid melt, with fluctuations in the crystal growth rate, convection fluctuations within the silicon melt due to temperature changes or dopant deposits of the n-type from the melt during the crystal growth process as well as solidifications of the silicon melt play another role.

The oxygen in the silicon substrate is activated as a donor after heat treatment at 450 ° C or higher, whereby the number of defects is achieved or dislocations due to the heat treatment of the silicon substrate  is pushed down so that the oxygen serves as getter material for eliminating defects.

It has recently been suggested the crystal growth process perform within a magnetic field, such as JP-PS 58-50 951 can be found. That in this publication discussed modified Czochralski methods (CZ method) is hereinafter abbreviated as the "MCZ method" (Magnetic Czochralski Method). When using this MCZ method, the convection is suppressed so that the crystal growth process under more stable conditions can expire. In addition, the amount of Stabilize and adjust oxygen (O) or boron (B) easily, with oxygen and boron pulled out of the crucible will come out of it. The crucible itself delivers these elements.

Because of the segregation or separation effect it is however, even with the MCZ process, the amount of N-type donors in the melt that are actually drawn crystal appears to adjust so that a fixed concentration value is obtained. Furthermore can the concentration of impurity doping from n-type fluctuate in the melt, between the Start of crystal growth and end of crystal growth, so that a concentration gradient with respect of the n-type impurity between the Top of the crystal at the start of crystal growth is formed, and obtained the bottom of the crystal which forms at the end of the crystal growth process.

The invention has for its object a solid Image recording device of the type mentioned at the beginning so that they have a more even distribution of n-type impurities and therefore less  Has errors. The aim of the invention is also to find a suitable one Method of manufacturing a solid state image pickup device to indicate with these properties. In addition, the invention is intended to provide a method for Manufacture of an n-type silicon substrate be used to manufacture a solid-state imaging device is suitable, the substrate being a desired one has high specific resistance and so is that there is no fixed noise pattern, none deteriorated image quality or other image deteriorating Apparitions due to crystal defects occur.

The solutions according to the invention are in the characterizing Parts of the respective subordinate claims specified. Advantageous further developments are the dependent claims refer to.

In a method according to the invention for producing a solid-state image recording device, a portion of the basic element Si is converted into n-type phosphor impurities (P), so that the substrate is converted into an n-type one, by atomic conversion as a result of Neutron irradiation of the p-type silicon wafer Si. In this way, a Si substrate with a specific resistance ρ _s of 10 to 100 ohm-cm or preferably with a specific resistance ρ _s of 40 to 60 ohm-cm is obtained. With the aid of this Si substrate, a solid-state image recording device with a plurality of photosensor areas and vertical and horizontal shift registers can then be produced, as already described.

According to a preferred process, the silicon substrate is by irradiating a wafer, e.g. B. with neutrons, the irradiation is carried out until the substrate has a desired specific resistance ρ _s . The wafer is previously cut out of a crystal that has been pulled using the MCZ method. This silicon substrate is preferably of the p-type before neutron irradiation, that is to say it takes on the same state as the grown crystal. In this state, its specific resistance ρ _{o is} at least ten times greater (100 ohm-cm or more) than the specific resistance ρ _s that is present after neutron irradiation. Should z. For example, if the desired specific resistance ρ _{s is} in the range of 40 to 50 ohm-cm, the original specific resistance ρ _{o should be} in the range of 680 to 1180 ohm-cm. The n-type contaminants, e.g. B. phosphorus impurities (P) are generated by neutron irradiation to convert the silicon substrate into an n-type one which has a low resistivity ρ _s of 10 to 100 ohm-cm or preferably 40 to 50 ohm-cm.

When manufacturing the Si crystal with high specific Resistance (100 ohm-cm or more) it is possible to use an undoped Si melt, the crystal even pulled using the MCZ process becomes. With the help of this undoped Si melt is still a p-type crystal with high resistivity obtained because p-contaminants, especially soluble Boron (B) supplied by the quartz crucible with the silicon melt is mixed.

The oxygen concentration in this Si crystal, i.e. in the Si substrate, is 2.0 × 10 ¹⁷ to 1.2 × 10 ¹⁸ atoms / cm ³ . This oxygen concentration can be adjusted by making the amount of oxygen drawn out of the quartz crucible during the crystal growth process using the MCZ method in accordance with the intensity of the applied magnetic field, the rotating speed of the crucible, the rotating speed of the crystal pulling device, etc ., is determined in a suitable manner.

On the silicon substrate produced in this way, Form solid-state imaging elements in that contaminants p-type in the main surface of the substrate be introduced, namely by ion implantation or suitable diffusion processes in order to achieve a To obtain the p-type well layer. Around photosensor areas and vertical and horizontal shift registers too generate, can also in the said main surface Ion implantation or suitable diffusion methods p-type, further trough areas from p-type, if necessary, and photosensor areas from n-type are introduced, in each case in the trough layer p-type.

According to the invention, since an n-type silicon substrate having a predetermined resistivity ρ _s can be manufactured by neutron irradiation of an output substrate, the initial resistivity ρ _{o can be} high so that no n-type impurity dopants are mixed with the crystal melt during the crystal growth process Need to become. This prevents a non-uniform doping concentration from occurring due to segregation or deposition of the impurities, as described above. Further, since the n-type phosphorus atoms (P) are generated by neutron irradiation of the Si substrate, an n-type substrate can be manufactured with any concentration precisely by adjusting the amount, strength, or duration of the uniform neutron irradiation. In the solid-state image recording device according to the invention, the potential barrier can thus be formed exactly, and specifically without a non-uniform doping distribution, so that fixed, strip-like noise patterns do not appear.

Since the specific resistance ρ _{s of} the silicon substrate is in the range from 10 to 100 ohm-cm, a solid-state image recording or image converter device can be produced with high image quality without the so-called blooming effect occurring or white dots appearing. If ρ _{s is} less than 10 ohm-cm, the concentration of the n-type impurities in the silicon substrate itself would be very high, which would mean that the potential barrier with regard to the outflow or overflow would be too close to the surface 1 a of the Silicon substrate would be located. In this case, the photosensor area could not collect sufficient signal charges. On the other hand, if the specific resistance ρ _s exceeds 100 Ohm-cm, the oxygen in the silicon substrate would be activated during the heat treatment during the manufacture of the solid-state image converter device. In this case, the properties of the device would change by changing the donor states.

According to the present invention, the oxygen concentration in the silicon substrate is at relatively high values, for example in the range from 2.0 × 10 ¹⁷ to 1.2 × 10 ¹⁸ atoms / cm ³ . The oxygen is thus able to effect a gettering effect with regard to core areas of crystal dislocations. It is thus possible to produce a solid-state image recording device with good properties which does not produce white dots.

According to the invention, a p-type crystal body is drawn, from which substrates or p-type wafers are cut out. These p-type substrates or wafers are converted into n-type substrates using neutron bombardment. The scope of neutron radiation can be controlled in a wide range. The neutron irradiation can take place, for example, in such a way that the intensity of the neutrons is set precisely. In this way, image recording devices with stable and uniform properties and precise specific resistances ρ _{s can be} produced.

A method for producing a solid-state image recording device according to the invention is characterized by the following method steps:
Pulling a p-type silicon single crystal from an undoped silicon melt, the silicon single crystal having a high resistance,
Formation of a silicon wafer from the silicon single crystal and irradiation of the silicon wafer with neutrons to produce an n-type silicon substrate with a resistance which is smaller than the resistance of the silicon single crystal, and
- Formation of the solid-state image recording device with a plurality of photosensor areas and shift registers on the silicon substrate.

The undoped silicon melt is in one Quartz crucible, which is heated by a heating device becomes. The silicon single crystal is made from the undoped silicon melt pulled out. Preferably The crucible contains boron, which is in the undoped silicon melt during the silicon single crystal growth process to form the p-type silicon single crystal melts into it. The boron thus comes directly from the crucible wall into the silicon melt. The step to pull of the p-type silicon single crystal includes one Step to control the melting rate of boron in the Silicon melt and the oxygen concentration inside the silicon melt. The oxygen also gets  directly from the crucible wall into this silicon melt. The step to control the melting rate of boron and the oxygen concentration occurs through adjustment the intensity of a surrounding or penetrating the crucible Magnetic field.

Advantageously, the boron melting rate and the Oxygen concentration in the silicon melt Control of the speed of rotation of the crucible adjustable.

In the practical process, the p-type silicon wafer made with a resistance greater than 100 ohm-cm is (specific electrical resistance). The resistance the silicon substrate is in the range of 10 ohm-cm to 100 ohm-cm.

The resistance value of the silicon single crystal is preferably p-type in the range from 680 ohm-cm to 1180 ohm-cm, while the resistance of the silicon substrate is in the range from 40 ohm-cm to 50 ohm-cm.

By the method according to the invention a uniform Distribution of phosphorus within the silicon substrate generated by neutron radiation.

Furthermore, a method according to the invention for producing a silicon substrate is distinguished by the following method steps:
Introducing an undoped silicon melt into a rotatable quartz crucible,
Generation of a magnetic field surrounding or passing through the crucible,
Setting the speed of rotation of the crucible to a predetermined value,
Pulling a p-type silicon single crystal from the silicon melt,
Formation of a silicon wafer from the silicon single crystal, and
- Irradiation of the silicon wafer with neutrons to produce an n-type silicon substrate.

The speed of rotation of the crucible is adjusted so that the resistance value of the silicon single crystal is larger than 100 ohm-cm. Furthermore, the speed of rotation of the crucible can be adjusted so that the oxygen concentration is in the range of 2.0 × 10 ¹⁷ to 2.0 × 10 ¹⁸ atoms / cm ³ . The n-type silicon substrate obtained by irradiating the silicon wafer with neutrons has a resistance value of 10 ohm-cm to 100 ohm-cm.

In the step of pulling the silicon single crystal melts Boron inside the quartz crucible into the silicon melt and serves as a p-type impurity. The boron is previously inside the crucible wall. The speed of rotation The crucible can be used to determine the amount of the boron melting into the silicon melt will.

A solid-state image recording device according to the invention is characterized by:
an n-type silicon substrate formed by irradiating a silicon single crystal with neutrons,
a plurality of photosensor elements on the substrate,
a charge transfer device for transferring electric charges generated in each of the photosensor elements, and
- A discharge or drain device for discharging excess charge carriers that have been generated as a result of excessive radiation of the photosensor elements.

The drawing shows an embodiment in addition to the prior art of the invention.

Fig. 1 is a schematic representation of a solid-state image pickup device according to the invention,

FIG. 2 shows an enlarged cross section through an essential area of the solid-state image recording device shown in FIG. 1, FIG.

Fig. 3 is a potential diagram along the line AA in Fig. 2,

Fig. 4 shows a cross section through a single crystal pulling device for the production of silicon single crystals by the Czochralski method and

Fig. 5 is an image of a strip-shaped noise pattern which is obtained with a conventional solid-state image pickup device.

The structure of a typical CCD solid-state image recording device or image-generating solid-state device is described below with reference to FIGS. 1 and 2. Fig. 1 shows the circuitry configuration of the image pickup device. According to the Fig. 1 and 2 includes the solid-state image pickup device, a plurality of photosensor regions 1, which are arranged along rows and columns and a matrix. Each photosensor region 1 represents a picture element on a common silicon substrate. On one side of each column of photosensor regions 1 there is a vertical shift register 2 of the CCD type. A common horizontal shift register 3 of the CCD type is located at one end of all shift registers 2 . Each vertical shift register 2 has transfer sections 2 a, whereby in each case a transfer section 2 is a respective an adjacent photosensor region 1 assigned. Minority charge carriers or minority carriers are generated in each photosensor area 1 in accordance with the amount of light impinging on them and transferred to the corresponding assigned transmission section 2 a of the respective shift register 2 of the corresponding column. In each shift register 2 , the minority carriers are then transmitted in sequence to the adjacent transmission sections 2 a , in the direction of the horizontal shift register 3 . The minority carriers are thus shifted towards the horizontal shift register 3 in the column direction. It is hereby achieved that the picture element signals generated by each photosensor area 1 as a function of the amount of light impinging on them can be output in turn for each horizontal line at an output terminal t of an output circuit of the horizontal shift register 3 .

If, in the solid-state image recording device described above, a photosensor area 1 is irradiated with strong light or light with a strong intensity, so that an excess of charge carriers is generated, these charge carriers are transferred from the latter to the shift register 2 without the influence of the photosensor area 1 , i.e. without the Photosensor area 1 can constrain or restrict the charge carriers generated. This leads to an overexposure or over-brightening effect (blooming effect). In order to avoid this blooming effect, an overflow drain region is provided in the vicinity of each photosensor region 1 in order to prevent too many charge carriers from being generated. This overflow drain area can be shown on the basis of a schematic cross-sectional representation through an essential part of the solid-state image recording device according to the invention in FIG . 2 recognize.

According to FIG. 2, a well layer 5 (potential well layer or well-layer) of the p-type is formed on the main surface 4 a of a silicon substrate 4 of the n-type by ion implantation or with the aid of diffusion techniques. An n-type photosensor area 1 is located in an area on or within the trough layer 5 on the side of the main surface 4 a and has also been produced by ion implantation or with the aid of diffusion techniques. The shift registers 2 and 3 and the photosensor areas 1 are divided or separated from one another by a channel stop area 6 within the main area 4 a . If necessary, a well region 7 of the p-type (well region) can be generated regionally within the shift register 2 , while through an region of the n-type the transmission section 8 of the shift register 2 on or within the region 7 on the side of the main surface 4 a is formed.

The potential distribution generated due to the charge carriers over the depth or thickness of the photosensor region 1 is shown in FIG. 3. Since a potential barrier with a predetermined height h with respect to the charge carriers is generated at a predetermined depth from the main surface 4 a due to the existing p-type well layer 5 , a leakage current of charge carriers into the substrate can be limited along the vertical axis. If, on the other hand, intense light strikes the photosensor area 1 , so that a large number of charge carriers is generated, then due to the suitably limited barrier height h, charge carriers which exceed this level can be diverted into the substrate via this barrier, so that that too many charge carriers get into the shift register 2 .

In the manufacture of the CCD solid-state imaging device according to the invention of the V-OFD type is first  a p-type silicon single crystal using the MCZ technique manufactured or drawn. When pulling the silicon single crystal p-type using the MCZ method becomes the oxygen concentration within the silicon single crystal by controlling a magnetic field set that is generated around a crucible or penetrates this, in which the silicon melt is located.

A device for carrying out the MCZ method (magnetic Czochralski method) is shown in FIG. 4. According to Fig. 4, this apparatus includes a quartz crucible 32 with molten silicon 33 from which a crystal 40 is pulled 31 for pulling a silicon crystal. This crucible 32 rotates about its central longitudinal axis with an adjustable rotational speed. It is also surrounded by a heating device 34 . This heating device 34 can be a cylindrical electrical heater 35 . Outside the heater 34 is a cylindrical heat insulating body or a water-cooled ironer 36 , if necessary. The entire device lies within a constant magnetic field which is generated by an external magnetic device 37 , for example by a permanent magnet or by an electromagnet. Reference number 38 denotes a silicon single crystal seed. This is held by a chuck 39 . The silicon single crystal seed is pulled upward by the chuck 39 and simultaneously rotated about the axis of rotation of the crucible 32 .

The electric heating device 34 is supplied with a direct current with 4% or less than 4% ripple or with a pulsating current or alternating current with a frequency which is equal to or greater than 1 kHz. The currents mentioned ensure that no unnecessary resonances are generated between the heating device 34 and the magnetic field.

The single crystal silicon seed 38 is pulled out from the surface of the molten silicon at a predetermined rate so that a silicon single crystal 40 can grow. By changing the rotational speed of the crucible 32 it is achieved in this case in particular that the oxygen concentration in the finished crystal 40 can also change. This is because the effective viscosity of the molten silicon in the crucible 32 increases by applying a magnetic field, and therefore, due to the relative rotation between the molten silicon and the rotating crucible, the frictional contact between the molten silicon 33 and the inner walls of the crucible 32 increased. This means that the oxygen dissolves in the walls of the crucible 32 , particularly if it is made of quartz, and passes into the molten silicon 33 . The oxygen concentration of the grown crystal 40 thus rises because, due to the increasing frictional contact, more and more oxygen is dissolved within the crucible walls, that is to say with increasing rotational speed of the crucible 32 relative to the molten silicon 33 . It has also been found that a higher oxygen concentration in crystal 40 can be obtained when a magnetic field is applied to the silicon melt, while the oxygen concentration is lower when no magnetic field is applied. In both cases, the speed of rotation of the crucible 32 was sufficiently high.

It is advantageous to have a high silicon single crystal Use oxygen concentration if this as Silicon substrate is said to serve an improved gettering effect to achieve. This is possible because the  Silicon single crystal with a higher growth rate or in comparison with increased growth rate for the conventional Czochralski process becomes. For example, according to the invention, the silicon single crystal Growth rate preferably greater or equal to 1.2 mm / min, with particularly good results in a speed range from 1.5 mm / min to 2.1 mm / min were achieved.

It is generally known that in the case of a silicon single crystal produced using the CZ method, the maximum single crystal growth rate V _max can be expressed by the following equation:

It is assumed here that the solid-liquid interface between the single crystal and the silicon melt is flat or flat and that there is no radial temperature gradient within the single crystal. The expression k denotes the thermal conductivity of the single crystal, the expression h the solidification heat, the expression ρ the density and the expression dT / dX the temperature gradient within the solid phase (of the single crystal) at the solid-liquid interface. The expression X indicates the distance or location on the longitudinal axis of the single crystal. Since the values k , h and ρ represent material properties, in order to increase the growth rate V _max it is necessary to increase the temperature gradient dT / dX . In the conventional CZ method described above, however, the temperature gradient dT / dX is severely limited, since the single crystal is heated by radiation from the surface of the molten silicon, through the inner walls of the crucible and through the heating device, so that in practice only one relative small growth rate is obtained.

As can be seen from the above description, This will accelerate the growth rate of the silicon single crystal or increase that the molten silicon heat supplied through the heater is reduced is so that the temperature of the melted Silicon lowered. Although through this influence the thermal or temperature gradient directly proportional is reduced as a result of the Stefan-Boltzmann law the heat radiated in the direction of the single crystal downsized to a much greater extent, so that due to receive an increase in the dT / dX of the net effect becomes. However, there is a risk that Reduction of the heat generated by the heating device to increase the growth rate the surface of the molten silicon solidified because the surface of the molten silicon of the inner furnace or gas atmosphere exposed and cooled by it. Hereby the range up to which the Temperature of the molten silicon can be reduced can.

The heating device of the device according to the invention is designed to produce a silicon single crystal that they are the surface of the molten silicon can apply enough heat to the silicon in the melted Keep condition. In particular, the Heating device according to an advantageous embodiment constructed to match the surface of the melted Silicon can add more heat than the rest Area of silicon so that the temperature of the melted Silicon can be minimized.

According to the invention, the silicon crystal or silicon single crystal is made from an undoped silicon melt drawn. This silicon melt was previously in one Quartz crucible introduced. There is a magnetic during the pulling process  DC magnetic field perpendicular to the direction along which the single crystal emerges from the Melt is pulled out. The single crystal body is by rotating the crucible or the crystal nucleus pulled or while rotating the single crystal pulling mechanism.

As the single crystal grows, the viscosity of the melt or silicon melt is adjusted by the application of the magnetic field, which means that the convection is also adjusted. By controlling the magnetic field intensity and the rotational speed of the single crystal pulling mechanism or the crucible, it is thus possible to determine the amount of oxygen and boron which is drawn out or diffused out of the quartz crucible in such a way that the oxygen concentration of the finished crystal and its resistance or have the specific electrical resistance ρ _o of the p-type silicon precisely determined.

In this way, a p-type silicon crystal having an oxygen concentration of 2 × 17 ¹⁷ to 1.2 × 10 ¹⁸ and an electrical resistivity of 680 to 1180 ohm-cm was obtained. The crystal was divided into wafers and then irradiated with neutrons using a furnace containing heavy water and a furnace containing light water. As a result, the p-type substrate 4 was thus converted into an n-type substrate with a specific electrical resistance ρ _s of 40 to 50 ohm-cm.

Finally, a V-OFD type solid-state image pickup device was fabricated by forming the photosensor areas 1 and the shift registers 2 and 3 on the substrate 4 as described above.

In the embodiment discussed above, the single crystal body generated with the help of the MCZ process, that is using a magnetic field. This has the Advantage that the oxygen concentration in the finished single crystal can be set precisely. However it is also possible the single crystal using other methods to draw.

According to the invention, since a p-type silicon substrate is converted into an n-type substrate by producing n-type phosphorus (P impurities) in the p-type silicon substrate by neutron irradiation, an uneven doping concentration can be avoided that would otherwise be obtained by adding n-type impurities before the crystal growth process. The intensity of the neutron radiation can also be increased in order to ensure safe operation, to obtain more uniform properties, to avoid the generation of solid noise patterns or white spots due to crystal defects, and to suppress the generation of dislocations so that the getter Effect can be adjusted based on the oxygen concentration by determining the specific resistance ρ _{s of} the substrate. The invention thus allows the production of a high-quality solid-state image converter device with a great many practical advantages.

Claims (25)

1. A process for producing a solid-state image recording device, characterized by the following process steps:
Pulling a p-type silicon single crystal ( 40 ) from an undoped silicon melt ( 33 ), the silicon single crystal ( 40 ) having a high resistance ( ρ _o ),
- Forming a silicon wafer from the silicon single crystal ( 40 ) and irradiating the silicon wafer with neutrons to produce a n-type silicon substrate ( 4 ) with a resistance ( ρ _s ) which is smaller than the resistance ( ρ _o ) of the silicon single crystal ( 40 ) , and
- Formation of the solid-state image recording device with a plurality of photosensor areas ( 1 ) and shift registers ( 2, 3 ) on the silicon substrate ( 4 ). 2. The method according to claim 1, characterized in that the undoped silicon melt ( 33 ) is in a quartz crucible ( 32 ) which is heated by a heating device ( 34 ), and that the silicon single crystal ( 40 ) from the undoped silicon melt ( 33 ) is pulled out. 3. The method according to claim 2, characterized in that the crucible ( 32 ) contains boron, which melts into the undoped silicon melt ( 33 ) during the silicon single crystal growth process to form the p-type silicon single crystal ( 40 ). 4. The method according to claim 3, characterized in that the step of pulling the p-type silicon single crystal ( 40 ) comprises a step of controlling the melting rate of the boron in the silicon melt ( 33 ) and the oxygen concentration within the silicon melt ( 33 ). 5. The method according to claim 4, characterized in that the step for controlling the melting rate of boron and the oxygen concentration is carried out by adjusting the intensity of a magnetic field surrounding the crucible ( 32 ). 6. The method according to claim 5, characterized in that the melting rate of boron and the oxygen concentration in the silicon melt ( 33 ) are also adjustable by controlling the speed of rotation of the crucible ( 32 ). 7. The method according to claim 1, characterized in that the p-type silicon wafer is made with a resistance greater than Is 100 ohm-cm. 8. The method according to claim 7, characterized in that the resistance value of the silicon substrate ( 4 ) is in the range of 10 ohm-cm to 100 ohm-cm. 9. The method according to claim 8, characterized in that the resistance value of the silicon single crystal ( 40 ) of the p-type is preferably in the range from 680 ohm-cm to 1180 ohm-cm, and in that the resistance value of the silicon substrate ( 4 ) in the range of 40 Ohm-cm to 50 ohm-cm. 10. The method according to claim 1, characterized in that a uniform distribution of phosphorus within the silicon substrate ( 4 ) is generated by neutron radiation. 11. A process for producing a silicon substrate, characterized by the following process steps:
Introducing an undoped silicon melt ( 33 ) into a rotatable quartz crucible ( 32 ),
Generating a magnetic field surrounding the crucible ( 32 ),
- Setting the speed of rotation of the crucible ( 32 ) to a predetermined value,
Pulling a p-type silicon single crystal ( 40 ) out of the silicon melt ( 33 ),
- Formation of a silicon wafer from the silicon single crystal ( 40 ), and
- Irradiation of the silicon wafer with neutrons to produce a silicon substrate ( 4 ) of the n-type. 12. The method according to claim 11, characterized in that the rotational speed of the crucible ( 32 ) is set so that the resistance value of the silicon single crystal ( 40 ) is greater than 100 ohm-cm. 13. The method according to claim 12, characterized in that the rotational speed of the crucible ( 32 ) is set so that the oxygen concentration is in the range from 2 × 10 ¹⁷ to 2 × 10 ¹⁸ atoms / cm ³ . 14. The method according to claim 13, characterized in that the silicon substrate ( 4 ) of the n-type, which has been obtained by irradiating the silicon wafer with neutrons, has a resistance value of 10 ohm-cm to 100 ohm-cm. 15. The method according to claim 11, characterized in that in the step of pulling the silicon single crystal ( 40 ) boron within the quartz crucible ( 32 ) melts into the silicon melt ( 33 ) and serves as a p-type impurity. 16. The method according to claim 15, characterized in that the rotational speed of the crucible ( 32 ) is set to determine the amount of boron melting into the silicon melt ( 33 ). 17. The method according to claim 16, characterized in that the speed of rotation of the crucible ( 32 ) for determining the amount of boron melting into the silicon melt ( 33 ) is set so that the silicon single crystal ( 40 ) has a resistance value of at least 100 ohm-cm . 18. The method according to claim 17, characterized in that the resistance value of the silicon single crystal ( 40 ) is preferably in the range from 680 ohm-cm to 1180 ohm-cm. 19. The method according to claim 17, characterized in that the silicon substrate ( 4 ) obtained by irradiating the silicon wafer with neutrons has a resistance value in the range from 10 ohm-cm to 100 ohm-cm. 20. The method according to claim 18, characterized in that the silicon substrate ( 4 ) obtained by irradiating the silicon wafer with neutrons has a resistance value in the range from 40 ohm-cm to 50 ohm-cm. 21. The method according to claim 11, characterized in that in the neutron irradiation step, phosphorus is formed in the silicon wafer for the production of the silicon substrate ( 4 ) of the n-type. 22. Solid-state image recording device, characterized by
a n-type silicon substrate ( 4 ) formed by irradiating a silicon single crystal with neutrons,
- a plurality of photosensor elements ( 1 ) on the substrate,
- A charge transfer device ( 2 a , 8 ) for transferring electrical charges that have been generated in each of the photosensor elements ( 1 ), and
- A discharge or discharge device for discharging excess charge carriers, which have been generated as a result of excessive radiation of the photosensor elements ( 1 ). 23. Solid-state image recording device according to claim 22, characterized in that the silicon substrate ( 4 ) of the n-type has a resistance value in the range from 10 ohm-cm to 100 ohm-cm. 24. Solid-state image recording device according to claim 23, characterized in that the silicon substrate ( 4 ) of the n-type has an oxygen concentration of 2 × 10 ¹⁷ to 2 × 10 ¹⁸ atoms / cm ³ . 25. Solid-state image recording device according to claim 24, characterized in that the silicon substrate ( 4 ) of the n-type from a silicon single crystal ( 40 ) of the p-type has been generated by irradiation with neutrons to form n-type impurities.